Atacama Large Millimeter/Submillimeter Array (ALMA) astronomers have captured incredible new images of Betelgeuse, a red supergiant star in the Orion constellation. These images reveal persistent hot patches and a distorted, non-spherical atmosphere.
This ALMA image shows the red supergiant star Betelgeuse. Image credits: ALMA / ESO / National Astronomical Observatory of Japan / NRAO / Dent others.
Betelgeuse, a red supergiant star, is approximately 8 million years old and located about 724 light-years away from Earth.
With a radius 1,400 times larger than the Sun, Betelgeuse is one of the largest stars known to astronomers.
Also referred to as Alpha Orionis or Alpha Ori, Betelgeuse is one of the brightest stars, emitting more light than 100,000 suns combined.
Scientists have long suspected that Betelgeuse’s surface is uneven and patchy, shaped by giant convective cells made up of hot gas rising from deep within the star.
“Betelgeuse (HD 39801, α Ori) is one of the two closest red supergiant stars and, as a prototype, the subject of intense study from radio to X-ray wavelengths,” said ESO astronomer Bill Dent and his colleagues.
“The relatively large angular diameter of the photosphere makes it solvable with current equipment.”
In August 2023, astronomers used ALMA to observe Betelgeuse and discovered that the star’s photosphere has an average temperature of about 2,300 K, with two significantly hotter regions in the northeast and southwest.
The researchers found that the northeastern hotspot, which is around 800 K warmer than its surroundings, closely matched observations from 2015, indicating its longevity of at least seven years.
They also observed a radial “waveform” that extends up to plus or minus 6% of the star’s apparent radius, concentrated in one sector of the star. However, the shape of this waveform has changed significantly since 2015, associated with intense convective activity within the star.
These convective activities promote the formation of molecules such as silicon monoxide and carbon monoxide, eventually leading to the creation of dust and potential loss of stellar mass into interstellar space.
“It will be fascinating to witness Betelgeuse’s ultimate fate as a supernova,” Dr. Dent remarked. “When it explodes, it will be visible from Earth even in broad daylight.”
The results of this study will be published in the journal astronomy and astrophysics.
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WRF Dent others. 2026. High-resolution observations of Betelgeuse with ALMA: Persistent structures in the inner atmosphere. A&Ain press. arXiv: 2608.19339
Source: www.sci.news
